In version 1.21.51 of Minecraft (Bedrock Edition), when you place a painting on a block and remove its root block, the painting does not fall immediately, but rather delays the fall. And the delay time is variable.Between approximately <1 to 4 seconds it will drop and fall out of the painting (item form), and it will fall in the order you placed the painting.

Steps to Reproduce:

1. Place a complete block

2. Place some paintings on it and destroy the source block

3. Observe the time delay and sequence of falling paintings

Observed Results:

The paintings fall in a delayed, sequential manner

Expected Results:

The paintings fall together without delay drop